Project Abstract This is an application for T32 support of The Johns Hopkins University School of Medicine Medical Scientist Training Program. The overall goal of our MSTP is to produce MD-PhD leaders who will use a robust, broad education in medicine and research training to improve health through highly innovative research, patient care and education. The Hopkins MSTP, founded in 1975, has a remarkable record of success in training physician scientists and continues to attract highly qualified applicants. The Program received 410-528 completed secondary applications annually between 2014 and 2018 and interviewed ~16% of these applicants. The process of applicant selection for interviews and admission is holistic, assessing an applicant?s unique experiences alongside traditional measures of academic achievement. Approximately 12 students enter the program each year. Admitted students have an average GPA of 3.91, an average MCAT score of 522, and demonstrate high motivation for careers in biomedical research and clinical medicine. The average time to degree matches the national average at 8.2 years. Of the 112 current MSTP students, 13% are underrepresented in medicine. There is also substantial focus on the recruitment of students from disadvantaged backgrounds and students with disabilities. Students typically take two years of medical school preclinical science courses before enrolling in one of 30 available graduate programs for approximately four years. Our MSTP students have over 1000 research faculty from whom they can select a PhD mentor. While completing their thesis research, students remain engaged in clinical education and take advanced courses. Students publish an average of 7.6 peer-reviewed papers before returning to medical school required clerkships and electives. Andrea Cox, MD, PhD has been directing the program since 2013, first as Co-Director with Robert Siliciano, MD, PhD, and as Director since 2015. She is a Professor of Medicine and Oncology, infectious disease specialist, active basic science and translational researcher, and distinguished teacher. Dr. Cox heads a diverse 38-member MD-PhD Committee that formulates policies for the Program, screens and recommends applicants for admission, and assists Dr. Cox in advising trainees and evaluating student progress. The Program has been highly successful in fulfilling the MSTP mission of training outstanding physician scientists. Of the MSTP-supported students who graduated between 2004 and 2019, 90% are currently in or have completed clinical residencies, primarily in top-tier programs. Among graduates from those years who have completed postgraduate training, 80 % remain in research-focused careers (74.7% research intense and 4.6% research related). Recent programmatic initiatives include increased engagement of Program alumni with current students, intensified scholarly efforts to understand and reverse continued underrepresentation of women and other groups in physician scientist careers, and increased exposure of current students to the full range of physician scientist career opportunities.